Barry learns that KF is on the loose and heads to the future with the plan to return a moment after he has left.
In 2024, he arrives and is attacked by Mirror Master and the Top.
Later he meets Cisco 2024 and starts learning how things fell to pieces after Iris died.
Barry 2024 doesn't know who Savitar is and is busy feeling sorry for himself. Team Flash has disintegrated but Savitar is trapped in the Speed Force.
We learn that at some point Cisco 2017 will fight KF 2017 and she will quite literally DISARM Cisco. Cisco will get terminator style prosthetic forearms and hands but he can't use his powers now.
KF 2024 reveals she is a worshiper of Savitar but won't reveal who he is.
Wally tried to fight Savitar and had his spine shattered. he is now catatonic and living in assisted living in his home.
Cisco 2024 begs 2017 Barry to stay and rebuild the team. At first Barry says no and after learning that Cisco 2024 has a resonance disruptor that prevents Barry from reaching time warp speeds, they have a heart to heart and Cisco 2024 shuts it off. Barry is about to leave and changes his mind and gathers Team Flash (minus KF of course) back together.
He goes to stop Mirror Master and the Top but is losing when Barry 2024 pulls his head out of his rear and takes the modified resonance device with him to aid Barry 2017. Together they stop the villains and Barry 2024 decides to keep Team Flash going.
he also gives 2017 Barry a device that contains the data on HOW the speed force trap was created by a physicist BUT she completed it in 2020 after Iris was killed. Barry 2024 hopes that the data can be decoded in time in the past to save Iris.
Barry heads back to 2017 and arrives a moment after he left.
Episode ends with Savitar confronting KF, she demands to know why she should trust him, Savitar then gets out of his armor to reveal who he is to her. Of course we don't see who he is, but she immediately swears loyalty.
I'm still thinking a corrupted future Barry or Barry from an alternate Earth.
Okay so somethings that Barry 2017 should have taken back with him to 2017 but didn't:
1. the resonance disruptor, if it affects him it will affect Savitar.
2. A 2024 model of the power inhibitor that kept Caitlyn from turning into KF, designed to resist extreme cold and can revert her back to Caitlyn.
3. Any and all camera footage of his fights with Savitar including the death of Iris so that he can see what will happen and make new strategies.
4. 2017 Barry should have stayed in 2024 to develop some type of anti speed weapons like the Legends used on RF.
Barry 2024's costume is a nice amalgam of 2017 Barry's suit and the classic comic book costume. It is NOT the one that we saw future Barry wear when he fought RF in his childhood home.
Also if Barry wants to save Iris perhaps warping her to Earth 2 or 3 for awhile until he traps him in the Speed Force?
So now we know that Savitar is a big guy, who has very broad shoulders, and short black hair.
Who do we know who is large, has very broad shoulders, has short black hair, and who Caitlin would trust instantly?
I think Savitar is Ronnie Raymond.